Polymerized ionic liquids (PIL) are being used in many advanced materials applications. An interesting subclass of PILs is composed of liquid PIL, LPIL. Such materials exhibit classical liquid properties and offer insight into the physics and physical chemistry of liquids and particles. We present an overview of LPIL and a classification scheme to usefully compartmentalize such materials for further design, optimization, and application. Several members of this class of LPIL are described in detail along with multiple applications. One member consists of organosiloxanes condensed on themselves to produce a novel type of solvent-free nanofluid. These materials are the first to experimentally illustrate polydispersity frustration of crystallization and to show that both freezing and glass transitions are lambda transitions. Another member comprises a functional core decorated with ionic liquid salts. Such materials can be used to mitigate embrittlement accompanying using nanofillers and to incorporate such nanofluids in diverse new materials and functional coatings. Linear LPIL offer similar advantages to those provided by molecular IL and promise to overcome leaching limitations in liquid supported membranes and polyeletrolyte membranes in batteries and fuel cells. Lastly, extension of PILs to polyurethanes and polyureas (PUs) and to polyesters (PEs) has resulted in the first known self-dispersing polyurethane and polyester dispersions (PUDs and PEDs, respectively). Several of their applications in stimuli responsive coatings and graphene dispersions are illustrated.